Counter network including photoresponsive elements



March 23, 1965 c. s. REIS ETAL COUNTER NETWORK INCLUDING PHOTORESPONSIVEELEMENTS 2 Sheets-Sheet 1 Original Filed Feb. 27, 1958 m oI mm mmCHARLES S. REIS AND IRWIN WUNDERMAN INVENTORS BY Q4 ATTORNEY March 23,1965 c. s. REIS ETAL COUNTER NETWORK INCLUDING FHOTORESPONSIVE ELEMENTSOriginal Filed Feb. 27, 1958 2 Sheets-Sheet 2 w v m w s mm R E M m R R TE A SD W SN U A E w of m N Y w M B R mv WT? a w 5 g m United StatesPatent ()fiice r nses Patented Mar. 23, 1965 4 Claims. ((31.250-269)This is a divisional application of our application Serial No. 717,965,filed on February 27, 1958, now abandoned, and entitled NetworkIncluding Photoresponsive Elements.

This invention relates generally to a network including photoresponsiveelements, and more particularly to a network of the above characterwhich is responsive to electrical input pulses.

It is a general object of the present invention to provide a multi-stagenetwork including photoresponsive resistance elements which isresponsive to electrical input pulses.

It is another object of the present invention to provide a multistagenetwork including photoresponsive resistance elements in which theenergization of stages is transferred to successive stages in responseto electrical pulses.

It is another object of the present invention to provide a multi-stagenetwork including photoresponsive resistance elements in which theenergization of stages may be transferred in either direction toadjacent stages in response to electrical pulses.

It is another object of the present invention to provide a multi-stagenetwork which is response to electrical pulses in which each of thestages includes a light source and at least one photoresponsiveresistance element.

It is another object of the present invention to provide a decadecounter employing light sources and photoresponsive resistance elements.

It is another object of the present invention to provide a counter whichemploy-s light sources and photoresponsive resistance elements arrangedin a plurality of stages.

It is another object of the present invention to provide a counter whichemploys light sources and photoresponsive resistance elements capable ofcounting forward or backward.

These and other objects of the invention will become more clearlyapparent from the following description when taken in conjunction withthe accompanying drawings.

Referring to the drawings:

FIGURE 1 is a schematic diagram of a network including photoresponsiveelements in accordance with the invention;

FIGURE 2 is a schematic diagram of a network including a pair of decadecounters connected in cascade;

FIGURE 3 is a schematic diagram of still another network which includesphotoresponsive elements;

FIGURE 4 is a network similar to that of FIGURE 1, providing means fortransferring the information in either irection;

FIGURE 5 is a network in accordance with the invention includingincandescent light sources;

FIGURE 6 shows a voltage-current characteristic for a light sourcesuitable for use in one embodiment of the invention; and

FIGURE 7 shows a voltage-current characteristic for a light sourcesuitable for use in another embodiment of the invention.

The network is generally in the form of a ring with the energization ofthe various stages being transferred successively around the ring inresponse to electrical input pulses.

The network illustrated in FIGURE 1 includes a plurality of stages11-20. Each of the stages includes a light source 22, a resistiveelement 23 serially connected with the light source, and aphotoresponsive resistance element 24 having one terminal connected tothe common junction of the light source 22 and resistive element 23, andits other terminal connected to an input line 26. A voltage source isapplied across the serially connected light source 22 and resistor 23 ofeach stage. As indicated, the voltage source is a negative source V andis connected to one terminal of each of the light sources through acurrent limiting resistor 27. As will presently become apparent, thevoltage source may be a positive source.

The light sources 22 may be of the type which become luminant uponapplication of a predetermined threshhold voltage, and once a sourcebecomes luminant, the voltage required to maintain the source in aluminant state drops to a value considerably less than the threshhold orbreakdown voltage required to transfer the same from a dark to aluminant condition. For example, each of the sources 22 may be a neonbulb which has a voltage current characteristic of the type indicatedgenerally in FIGURE 6. However, as will become presently apparent, thelight sources may be incandescent lamps connected in circuit with aphotoresponsive element.

Operation of the circuit of FIGURE 1 is as follows: Assume for purposesof illustration that the light source 20-22 is luminant, that is, thatthe count on the ring counter is zero. The light from the light source20-22 impinges upon the photoresponsive element 11-24 thereby reducingits resistance. Application of a positive electrical pulse 28 to theline 26 will be transmitted through the photoresponsive element 11-2 tothe common terminal of the light source 11-22 and resistive element11-23. This pulse will increase the voltage across the light source11-22 above the break-down voltage and the source be comes luminant. Thecurrent which flows through the light source 11-22 during the pulseinterval is considerable since the resistance through the element 11-22and 11-24 is very low. The current limiting resistor 27 limits theamount of current which may flow from the voltage source -V. As aresult, a large percentage of the limited current will fiow through thelight source 11-22. The current through the light source 20-22 will. berelatively low and the same source 20-22 reverts to its non-conductingdark state. Upon termination of the pulse 28, the light source 20-22 isdark and the source 11-22 is energized or illuminated. Thus uponapplication of one pulse, the energization has been transferred from thelight source 20-22 to the light source 11-22. Application of subsequentpulses 28 will serve to transfer the energization of the light source 22down the chain to the right in the illustration. The apparatus isconnected in the form of a ring whereby the tenth pulse is appliedthrough the photoconductive element 23-24 to the light source 20-22 toreturn the same to a zero count. It is of course to be understood thatreference to a decade counter is merely for illustration since thecircuit may be employed to divide by any desired number.

In applications, such as in a decade counter, the count may be on anyone of the stages upon completion of a particular count. Thus, it isdesirable to be able to reset the counter to zero prior to beginning anew count. Referring to the figure, an input reset line 29 is connectedthrough a resistor 30 to the common terminal of the light source 20-22and the resistor 20-23. Upon application of a positive pulse 31 havingsufficient amplitude to make the stage 2% conducting the conductingstate will be automatically transferred to the stage 20 and whateverstage 7 going operated at rates up to 30 cycles.

is energized will become de-energized in the manner previouslydescribed.

For counting larger counts one may employ more stages. However, indecimal systems, it is preferable to cascade a plurality of decadecounters thereby reducing the number of stages required for high counts.Referring to FIGURE 2 a suitable means for forming a pulse every tenthinput electrical pulse 28 to the counter is shown. In FIGURE 2 a pair ofdecade counters 32 and 33 are illustrated with only the first and laststage of the decade counter 32 shown and the first two and last stage ofthe counter 33 shown. Since these counters are identical to the ringcounters shown in FIGURE 1, they carry like reference numerals toindicate like parts. The circuit which serves to form an additionalpulse 3 5 for application to the second decade 33 comprises a pair ofphotoresponsive elements 36 and 37, and a capacitor 33. Thephotoresponsive element 36 is arranged to be illuminated by the lightsource 1922. The photoresponsive element 36' has one terminal connectedto a voltage supply +V and its other terminal connected to one terminalof the capacitor 38 whose other terminal is grounded. Thus, when thelight source 19-22 is luminant, it serves to reduce the resistance ofthe photoresponsive element 36 whereby substantially full voltage +V isapplied to the capacitor 33 to charge the same. The photoresponsiveelement 37 'is arranged adjacent to the light source 29-22. Thus, whenthe count is transferred from 9 to 0 that is, the tenth input pulse thephotoresponsive element 37 is illuminated thereby reducing itsresistance. The voltage on the capacitor is applied to thephotoresponsive el ments 24 of the counter 33 and serves to energize thenext succeeding stage in the counter, as previously de scribed.Subsequent cascaded decades may be supplied and connected in a similarfashion whereby an output pulse is formed every tenth, hundredth,thousandth, etc., to provide means for counting any desired numbers.

'Apparatus was constructed in accordance with the disclosure of FIGURES1 and 2 and the elements had the following values:

Light sources 22NE2 Resistors 2347K ohms Photoresponsive devices 24:

megohoms dark 15K ohms light Photoresistive elements 36 and 37:

' 15 megohms dark 15K ohms light Capacitor 38.1 microfarad Voltages:

V-200 volts V 200 volts |V--5 0-200 volts R27-39OK Pulses 2840100 voltsReset pulses 3110O volts Apparatus constructed in accordance with thefore- The rate of operation being dependent only upon the response timeof the photoresponsive elements.

The embodiment of FIGURE 3 shows a ring counter in which only the threeleft-hand stages 2 11 and 12, and two of the right-hand stages 18 and 19are shown since all of the other stages are identical. A plurality oflight sources 42 which may be of the type previously described areserially connected with photoresponsive elements 43 across a bias source+V. A current limiting resistor45 is serially connected with the voltagesource +V to limit the current drawn by the energized stage. Aphotoresponsive element 44 has one terminal connected to the commonjunction of the light source 42 and photoresponsive element 43 and itsother terminal connected to the line 46. Photoresponsive elements s7 areconnected in shunt with their respective light source 42.

Operation of the circuit is as follows: When a negative pulse 49 isapplied to the line 46, it serves to increase the voltage across theelement 42 thereby energizing the same. The photoresponsive element 43is arranged to receive light from the light source 42 and thereby hasits resistance decreased. When the pulse 49 terminates, the associatedlight source 42 remains illuminated since the resistance of the path isconsiderably reduced. The photoresponsive element 47 associated with apreceding light source is connected to receive light from the succeedinglight source 42. The element 47 is connected in shunt with the precedinglight source. When it is illuminated, it provides a low resistance pathin shunt with the light source thereby extinguishing the same. Lightfrom the source 42 also impinges on the photoresponsive element :4 ofthe next adjacent stage thereby conditioning the same to transmit thenext input pulse to its associated .light source to thereby ignite orenergize the next succeeding stage. Operation of the circuit in responseto pulses is to propagate the energized or lit stage down the counterfrom one stage to the next successive stage.

It is noted with respect to the circuit of FIGURE 3 that thevoltage-current characteristics of the lightsources 22 are notimportant. The photoresponsive element 43 in series with the associatedlamp gives the required voltage current characteristics. That is, thevoltage required to sustain the stage drops as the resistance 43 isreduced. Further, the stages extinguish since the photo responsiveelements 47 provide the extinguishing.

To reset the counter to zero, a pulse 51 is applied to the line 52 whichpulse serves to ignite the associated light source 2tl-42. The pulse 51is also applied to an electronic or other suitable switch 53 and servesto open the circuit thereby removing the biasing voltage +V for aninstant whereby any energizing stage becomes de-energized. The switch isthen closed prior to termination of the pulse 51 whereby the stage 20 isignited or energized.

Referring to FIGURE 4, a circuit similar to'that of FIGURE 1 is shown.The various polarities have been reversed to show that a circuit may beconstructed to operate with either polarity. The circuit of FIGURE 4 isarranged whereby the ignited or energized stage may be transferred tothe right or left by applying pulses 61 and 62 to the lines 63 and 64respectively. The circuit includes a plurality of stages indicated as20, 11, 12, 13, etc. Each of said stages includes a light source 22, aresistor 23 connected in series with the light source to receive thebias potential -|-V through a current limiting resistor 27, andphotoresponsive elements 24a and 24b. The elements 24 each have oneterminal connected to the line 63 While the elements 24b have oneterminal connected to the line 64. The elements 24a are associated withsucceeding stages while the elements 24b are associated with precedingstages. The elements 24a are disposed to be illuminated by the precedinglight source, while the elements 24b by the succeeding light source.

Operation of the circuit is apparent from the description of theoperation of the circuit of FIGURE 1. It is apparent that application ofpulses 61 to the line 63 will serve to transmit the energized stage downthe series of stages in response to the pulses 61. Pulses 62 on the line64 will serve to transmit pulses in an opposite dir ti The interstagenetwork described with reference to FIG- URE 2 formed pulses whencounting in one direction. A similar network may be employed for formingpulses when counting in an opposite direction. Circuits of the typeshown in FIGURE 4 can then be cascaded.

As previously described, other types of light sources may be employed inthe multi-stage network of the invention. Thus, incandescent lightsources having voltage-current characteristics of the type shown inFIGURE 7 are suitable. A multi-stage network employing incandescentlamps is illustrated in FIGURE 5. The network shown is a decade counter.Only the first four and last two Stages a e illustrated in the drawing.Each stage 1ncludes an incandescent source 71 connected in series With aphotoresponsive element 72 and a photoresponsive element 73 having oneterminal connected to the junction of the source 71 and element 72, andits other terminal to the input line 26. Resistor 27 is conected inseries with the voltage supply V and provides a substantially constantcurrent to the network.

Assuming that regeneration in each stage, that is, a drop in voltagerequired to maintain the stage energized occurs at one-half ratedcurrent, operation of the circuit to transfer the energization from onestage to the next in response to input pulses 28 is as follows: When thelamp current in a state exceeds the regenerative value, the lamp goes onand nearly all the current flows in this stage. The succeeding stage isconditioned since its element 73 is illuminated. Application of a pulse28 will cause the next lamp to light. If the pulse is of sutlicientamplitude, the current through the lamp will be such that the remainingcurrent is insufficient to maintain the preceding lamp. The lit stage istransferred. By employing extinguishing photoresponsive elements asshown in FIGURE 3, the circuit may be made to operate in a more positivemanner.

Thus, it is seen that a novel network including photoresistive elementshas been supplied. The network is useful for counting input pulses orfor registering or transferring information. The network may employ anytype of light source in conjunction with the photoresponsive elements.

We claim:

1. A counter comprising input means, first and second networks eachincluding a plurality of stages, and for each of the stages at least onelight source and a resistive means connected in series with said lightsource, said light source and resistive means having a voltage abovewhich the lig t source becomes luminant and a lower voltage serving tosustain the same, means for applying a bias voltage across said lightsource and resistive means, said bias voltage being of such value thatit serves to maintain the source luminant once it is triggered, at leastone photoresponsive resistance element having a pair of terminals, oneterminal being connected between said light source and resistive meansand the other terminal being connected to receive electrical inputpulses appearing at said input means, said photoresponsive element beingdisposed to re ceive illumination from the light source of the nextpreceding stage, the counter further comprising a pair ofphotoresponsive elements serially connected, one of said pair ofphotoresponsive elements having its free terminal connected to applyinput pulses to the second network, the other of said pair ofphotoresponsive elements being connected to a voltage supply, said oneof said pair of photoresponsive elements being arranged to beilluminated by the light source associated with the first stage of thefirst network, said other of said pair of photoresponsive elements beingarranged to be illuminated by the light source associated with the laststage of said first network, and a capacitor connected to the commonterminal of said pair of photoresponsive elements and adapted to becharged to the applied voltage when said other of said pair ofphotoresponsive elements is illuminated and serving to discharge throughsaid one of said pair of photoresponsive elements when the light sourceof the first stage is illuminated to thereby provide an input pulse tothe second network.

2. A counter as in claim 1 wherein each stage of one of the first andsecond networks includes at least one additional photoresponsiveresistance element having a pair of terminals, one terminal beingconnected between said light source and resistive element and the otherterminal connected to receive electrical input pulses appearing at saidinput means, said one additional photoresponsive resistance elementbeing disposed to receive illumination from the light source of the nextsucceeding stage.

3. A counter as in claim 1 wherein one of the first and second networksincludes ten stages to form a decade counter.

4. A counter as in claim 1 wherein for each stage said resistive meansconnected in series with the light source is a photoresponsive resistiveelement and wherein for each stage an additional photoresponsive elementis connected in shunt with said light source and adapted to beilluminated by the light source of the next succeeding stage.

References Cited by the Examiner UNITED STATES PATENTS 2,895,054 7/59Loebner 2502l3 2,900,522 8/59 Reis 250-213 2,907,001 9/59 Loebner 2502132,949,538 8/60 Tomlinson 2502l3 2,984,749 5/61 Ross 250209 2,985,7635/61 Ross 250-213 2,988,645 6/61 Wilmotte 250209 2,996,622 8/61 Acton250-208 2,997,596 8/61 Vize 250213 2,999,165 9/61 Lieb 250208 OTHERREFERENCES Standeven, J. D., Opto-Electronic Ring Counter, IBM TechnicalDisclosure Bulletin, volume 2, No. 2, 8/ 59.

RALPH G. NELSON, Primary Examiner. DARYL W. COOK, WALTER W. BURNS,Examiners.

1. A COUNTER COMPRISING INPUT MEANS, FIRST AND SECOND NETWORKS EACHINCLUDING A PLURALITY OF STAGES, AND FOR EACH OF THE STAGES AT LEAST ONELIGHT SOURCE AND A RESISTIVE MEANS CONNECTED IN SERIES WITH SAID LIGHTSOURCE, SAID LIGHT SOURCE AND RESISTIVE MEANS HAVING A VOLTAGE ABOVEWHICH THE LIGHT SOURCE BECOMES LUMINANT AND A LOWER VOLTAGE SERVING TOSUSTAIN THE SAME, MEANS FOR APPLYING A BIAS VOLTAGE ACROSS SAID LIGHTSOURCE AND RESISTIVE MEANS, SAID BIAS VOLTAGE BEING OF SUCH VALUE THATIT SERVES TO MAINTAIN THE SOURCE LUMINANT ONCE IT IS TRIGGERED, AT LEASTONE PHOTORESPONSIVE RESISTANCE ELEMENT HAVING A PAIR OF TERMINALS, ONETERMINAL BEING CONNECTED BETWEEN SAID LIGHT SOURCE AND RESISTIVE MEANSAND THE OTHER TERMINAL BEING CONNECTED TO RECEIVE ELECTRICAL INPUTPULSES APPEARING AT SAID INPUT MEANS, SAID PHOTORESPONSIVE ELEMENT BEINGDISPOSED TO RECEIVE ILLUMINATION FROM THE LIGHT SOURCE OF THE NEXTPRECEDING STAGE, THE COUNTER FURTHER COMPRISING A PAIR OFPHOTORESPONSIVE ELEMENTS SERIALLY CONNECTED, ONE OF SAID PAIR OFPHOTORESPONSIVE ELEMENTS HAVING ITS FREE TERMINAL CONNECTED TO APPLYIMPUT PULSES TO THE SECOND NETWORK THE OTHER OF SAID PAIR OFPHOTORESPONSIVE ELEMENTS BEING CONNECTED TO A VOLTAGE SUPPLY, SAID ONEOF SAID PAIR OF PHOTORESPONSIVE ELEMENTS BEING ARRANGED TO BEILLUMINATED BY THE LIGHT SOURCE ASSOCIATED WITH THE FIRST STAGE OF THEFIRST NETWORK, SAID OTHER OF SAID PAIR OF PHOTORESPONSIVE ELEMENTS BEINGARRANGED TO BE ILLUMINATED BY THE LIGHT SOURCE ASSOCIATLED WITH THE LASTSTAGE OF SAID FIRST NETWORK, AND A CAPACITOR CONNECTED TO THE COMMONTERMINAL OF SAID PAIR OF PHOTORESPONISVE ELEMENTS AND ADAPTED TO BECHARGED TO BE APPLIED VOLTAGE WHEN SAID OTHER OF SAID PAIR OFPHOTORESPONSIVE ELEMENTS IS ILLUMINATED AND SERVING TO DISCHARGE THROUGHSAID ONE OF SAID PAIR OF PHOTORESPONSIVE ELEMENTS WHEN THE LIGHT SOURCEOF THE FIRST STAGE IS ILLUMINATED TO THEREBY PROVIDE AN INPUT PULSE TOTHE SECOND NETWORK.